They are giant tidal waves that begin from the depth of oceans and violently land on seashores. Underwater earthquakes and volcanic eruptions are the primary causes of tsunamis. Initially, these tidal waves are small where the sea is deep; they can grow up to a hundred feet after reaching shallow waters.
The largest tsunami ever recorded hit Lituya Bay, Alaska, on July 9, 1958. The massive wave was 1,700 feet tall, and it destroyed everything in a 5 square mile radius. However, the average tsunami wave height is only 3 metres (10 feet).
Drastic submarine activities such as earthquakes, underwater volcanic eruptions, underwater landslides, glacier calvings, and nuclear tests are the prime causes of a tsunami. However, meteorite fall has also caused tsunamis. Earthquakes and volcanic eruptions are the most frequent causes of tsunamis.
Tsunamis are as fast as a jet plane in deep waters, but they slow down upon reaching shores. It is nearly impossible to track a tsunami on time. A satellite must be passing over the mega wave to detect it, which is the rarest of the rare occurrence.
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There is no accurate detection system to identify the occurrence of a tsunami within time, even if the system has the data on the magnitude and location of an underwater earthquake. Tsunami Warning Systems play a key role in evacuating the population within time.
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A sensor network that observes seismic alerts to predict an upcoming tsunami wave.
Tsunami Warning Systems have two types
Such systems cover a vast area across international borders and seas
Local warning systems also detect a shorter range of seismic activities. The Regional warning systems can relay information in a maximum of 15 minutes.
Mitigation measures help in minimising the potential damage caused by tsunamis. Nations like Japan, Indonesia, the Philippines, Alaska, and Chile are the most prone to tsunami destruction. Japan has been proactive in preventing damage. They have installed 39 feet (12 metres) walls at populated coasts. There is still a risk factor of the waves overlapping the walls.
The 2011 Tōhoku earthquake and tsunami caused the horrific Fukushima Daiichi nuclear disaster. Even though there were protective walls, the waves were large and powerful enough to overrun the barricades.
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An earthquake under the deep ocean causes the chaotic displacement of water. This event marks the beginning of a tsunami. The displaced water takes the form of a wave and moves at a tremendous pace. As this wave moves closer and closer to the shore, its speed decreases but the height increases. A tsunami doesn’t stop after hitting the land; it only ends when its energy is exhausted. In some instances, an earthquake causes underwater landslides, resulting in a tsunami. An underwater volcano causes a tsunami by either erupting or collapsing. The only instance of a tsunami caused by a meteorite was in 1958, in Lituya Bay, Alaska.
Tsunamis are natural disasters capable of destroying thousands of trees, homes, buildings, and lives. The characteristics of tsunami waves have paved the way to create modern tsunami warning systems. These systems allow the authorities and people to follow mitigation measures for tsunami waves within a safe time window. We cannot control natural phenomena like earthquakes and volcanic eruptions, but we can bolster our preparedness whenever an imminent tsunami hits our seashores. The best advice for an upcoming tsunami is to seek higher ground or tsunami shelters.
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